The invention relates to a tool coupling for the attachment of a tool to a rotating machine spindle.
A tool coupling for the attachment of a tool to a rotating machine spindle is known from DE-A-3,314,591. The tool comprises a frusto-conical centering journal which engages in a taper socket fast with the spindle. The end of the centering journal of larger diameter merges into a tool support shoulder extending at right angles to the axis of rotation and abutting, when the tool is coupled, on an abutment face which forms the end face of the taper socket. For torque transmission a coupling engaging by shape is provided. The angle of conicity of the centering journal is made slightly smaller than the angle of conicity of the taper socket and the centering journal is dimensioned so that it comes to abut in the taper socket firstly in the region of its smaller end and in tightening is driven with radial deformation into the taper socket, until the support shoulder rests against the abutment face.
In this, as also in other known tool couplings the spindle reception opening which receives the cylindrical or frusto-conical shank widens out appreciably, by reason of centrifugal forces when the machine spindle is driven at very high rotation rate for example of 20,000 r.p.m. or more. This has the consequence that the tool shank is no longer radially clamped in uniformly over its entire length, and radial play occurs.
The invention is directed towards provision of a tool coupling which guides the tool both axially and radially even at very high rotation rates, and requires comparatively small tool-changing forces.